[noobCNC]

Anyone do their part to save the world by recycling metal chips? (I presume it may include having to sort out the chips (i.e. clear the collector between different runs of different materials) and also cleaning off the coolant/oil residue?

Or straight to the trash?

[WOTDesigns]

I won't lie.. I do it all for the money :-)

I have only had my little CNC running for a few months and have a cheap $15 walmart trash can almost full of chips and several Homer buckets full of scrap. I use mist and the chips are dry every time I pull them out. I have done primarily aluminum but when I need to cut wood or steel our whatever I clean her out and vacuum the remaining chips out with a wet/dry vac that had a remote on the handle which hangs right under my keyboard. when I'm done I clean again and toss the chips that aren't AL and use my normal shop vac to clean the small stuff.

my buddy recycles a ton of al at a time and gets MUCH better price than I do so I will just go with him when he goes. $.90/lb on scrap and $.75/lb on chips buys a lot of beer and buffalo wings.

[buffaloguy]

Unless you just talking about a few pounds, its always worth saving the scrap. You will learn very fast that when you return aluminum chips, they will use a magnet and look for steel chips. If they find any steel they automatically call it 'dirty chips' and will will give you minimum price per lb. Instead of say $.60 a lb, they give you $.10 if your lucky. So Very important to keep steel & alum. seperate. AS for 'Wet chips', thats more up to you. I let them sit in the machine over night to drain then put in a steel drum w/ a hole on the bottom. I dont recycle enough chips to spin the excess out of them but I do give the common courtesy (to the scrap yard workers) of not leaving a gallon or more of liquid in the drums.

I get about 4-6 barrels of alum chips every 4 months or so and get about $650-700 for it. I buy lunch for my co-workers and keep the rest since I am the only machinist at the place.

[WOTDesigns]

hmmm... might start dumping mine (much smaller quantity than yours) into a flat tub first and run a magnet through to get stay steel

[noobCNC]

I guess you got hookups for recycling locations but do most recycling places take scrap? Theres a scrap yard here but I dont know if they take scrap chips? They probably dont mind taking for free but I duno if they can land me a good price for it.

The most annoying thing is I switch materials quickly so its a pain in the arse to have to clean the enclosure and mill completely to sort chips out. And I do plastic parts too.

hmmm... might start dumping mine (much smaller quantity than yours) into a flat tub first and run a magnet through to get stay steel

Haha, but unfortunately 304 stainless steel for example is not ferromagnetic (just very very weakly in some cases of treatment/purity) so you need some other method of separation. Maybe density. So fill your tub with some liquid of the right specific weight to float alumminum but sink higher density ferrous materials and mix well so they mass separate.

[noobCNC]

Unless you just talking about a few pounds, its always worth saving the scrap. You will learn very fast that when you return aluminum chips, they will use a magnet and look for steel chips. If they find any steel they automatically call it 'dirty chips' and will will give you minimum price per lb. Instead of say $.60 a lb, they give you $.10 if your lucky. So Very important to keep steel & alum. seperate. AS for 'Wet chips', thats more up to you. I let them sit in the machine over night to drain then put in a steel drum w/ a hole on the bottom. I dont recycle enough chips to spin the excess out of them but I do give the common courtesy (to the scrap yard workers) of not leaving a gallon or more of liquid in the drums.

I get about 4-6 barrels of alum chips every 4 months or so and get about $650-700 for it. I buy lunch for my co-workers and keep the rest since I am the only machinist at the place.

Wow 700 bucks is good return! How did you find out about the place? Just drive up to the local scrap yard or recycling plant? Also, out of curiosity, do you run a home shop for hobby or business? How did you manage 4-6 barrels of aluminum!?

Also did they really just use a magnet to check? If someone is doing aluminum alloy and austenitic stainless steel (e.g. 304 stainless), they wont be able to separate using a magnet since 304 is not ferromagnetic in atmospheric conditions and temperature. Just doesnt seem like a 'fail proof' method of determining 'purity' of the aluminum chips in question being sold for recycling.

[WOTDesigns]

I guess you got hookups for recycling locations but do most recycling places take scrap? Theres a scrap yard here but I dont know if they take scrap chips? They probably dont mind taking for free but I duno if they can land me a good price for it.

The most annoying thing is I switch materials quickly so its a pain in the arse to have to clean the enclosure and mill completely to sort chips out. And I do plastic parts too.



Haha, but unfortunately 304 stainless steel for example is not ferromagnetic (just very very weakly in some cases of treatment/purity) so you need some other method of separation. Maybe density. So fill your tub with some liquid of the right specific weight to float alumminum but sink higher density ferrous materials and mix well so they mass separate.

I haven't cut any stainless yet, but if I do... shhh... it won't stick to their magnet either

we are taking about parts per million here, less steel in my AL tub than rodent parts in a Big Mac... and I eat those anyways.

not all places take chips, but almost anyone will take solid scraps. call around PRICES VARY! one place will give me $.45 for solid and another will do $.65. its also based on weight. they don't really want to waste their time with someone bringing 20lb so they pay less; thats why I have piggy backed with my buddy. when I did it before it was just scrap not chips though. I have also just traded him weight of my scrapfor weight in his plates. he gets about 3 tons of scrap a year and its mixed stainle$$, AL, Steel, brass and stuff I've never even heard of even it starts getting to his "expensive" jobs.

[Shane1234]

I guess you got hookups for recycling locations but do most recycling places take scrap? Theres a scrap yard here but I dont know if they take scrap chips? They probably dont mind taking for free but I duno if they can land me a good price for it.

The most annoying thing is I switch materials quickly so its a pain in the arse to have to clean the enclosure and mill completely to sort chips out. And I do plastic parts too.



Haha, but unfortunately 304 stainless steel for example is not ferromagnetic (just very very weakly in some cases of treatment/purity) so you need some other method of separation. Maybe density. So fill your tub with some liquid of the right specific weight to float alumminum but sink higher density ferrous materials and mix well so they mass separate.

Thats the same issue i run into at my work, we switch between stainless 303 & 304, to 1018, to 4140, to delrin, to uhmw, to nylon, to bronze, to brass, to alum, etc. glorified job shop at your service! 93% of our work is stainless, while another 3% is 1018 & 4140, and another 3 percent is delrin & uhmw. our scrap guys told us they dont want our chips, just chunks, so for years we toss it in the dumpster....... however we just moved last march, and a scrap yard is only 3 blocks away, it might be worthwhile to start saving chips again and not have such a long drive just to turn those in (was 40 minutes, now 3 blocks).

[buffaloguy]

I work at a place where I am the only machinist and run the only cnc. My boss doesnt care what happens to the scrap so I keep them and return them! I mainly work with aluminum and drill/bore holes 1.0-1.25" and 2-9" deep in 1.625" al. So needless to say I get plenty of chips. Plus I pack them in the barrel to maximize weight. I work with 2011 which chips up better then 6061.

To keep the chips seperated from another type starts off at the machine. Thats teh most important step. Clean the machine of any unwanted metals and then have dedicated barrles for each type of metal you work with. Keeping SS out of the alum is hard to seperate once mixed but SS is more per Lb so thats your incentive to keep the machine clean! Also its important not to think a handful of questionable mixed turnings is ok to put in the middle of the barrel. Places usually have a magnetic pole they stick down and probe around.

I recommend calling around to local yards, find out what the going price is for a metal and see what one offers the most. You be suprised on how many places vary. I first started off working at my family machine shop/business and got to return all the metal scrap so I became quite familiar with the cashiers and employees there. I made friends and my price per lb slowly raised. Also, the cashier is your best friend, they can alter the base price if they like you. I once bought raffle tickets from a cashier with a family member in the hospital w/ cancer. I bought 4 tickets at 20 a pop and the very next trip returning metal, I saw a huge increase in price per lb. She said I was one of a few select customers with that pricing. Also said thats good for anyone from my dads shop too! It pays to be nice (no pun intended lol)

Plus it feels good to recycle!!!

[noobCNC]

Do you even throw your pop cans and other household disposable aluminum in the mix or do you let the municipal services take those for recycling the old fashioned way?

Yea its a good idea. Maybe Ill drive up to get a rough idea if they accept scrap or not.

[WOTDesigns]

lol... same 45 gallon walmart cans (one in the laundry room, one in front of the garage) average between $50 and $70 depending on how well the cans are crushed when I take those to the recycle center behind my local Vons (grocery store). that happens about every other month and I like getting good steaks or ribs with the money. pretty convenient.

please don't question the of drinking 45 gallons worth of crushed can in two months... its not ALL beer

[buffaloguy]

So you think you get more from crushing cans that just returning them? If that was my tote of cans, it would be all beer LOL

lol... same 45 gallon walmart cans (one in the laundry room, one in front of the garage) average between $50 and $70 depending on how well the cans are crushed when I take those to the recycle center behind my local Vons (grocery store). that happens about every other month and I like getting good steaks or ribs with the money. pretty convenient.

please don't question the of drinking 45 gallons worth of crushed can in two months... its not ALL beer

[WOTDesigns]

I get more per TRASH can by crushing them

[noobCNC]

Prior to deciding on recycling, did you also consider even remotely, casting a new block of now unknown purity material from the chips?

[WOTDesigns]

no. if I were seeking new hobbies forging would be pretty high on the list, but as it stands I am months behind my plan for "production" and still have a list of things on my wish-list that might make me money.

honestly its kind of a PITA to have to clean everything just to cut steel then clean it again befor cutting AL just to keep the chips from mixing. I do it now because I do very little steel. next week I get to learn to scrape my new gibs and just the thought of cleaning up wood chips from pocketing a jig for them has me thinking I will just cut the wood into pieces on the bandsaw and screw them to another piece just to avoid cleaning the mill twice.

[noobCNC]

I know the feeling. The plus side is there is always something in the horizon so you are never dry of ideas to do, but it does get frustrating if you are backlogged.

Yeah it is a pain. The other annoying thing is, if you have say just one shop vac, that filter is a PITA to clean also. Alternatively you can do what some do and fabricate some sort of primary dust collector using cyclonic separation that is then in tandem with a secondary vacuum system like a shop vac which is providing the pumping. This essentially makes the cleaning filter part a nonissue since if designed properly the dust/chips should primarily be collecting in the primary stage collector. Thats one of my future projects. So I guess then you can then keep 1 bin for each material you do and its as easy as vacuuming the whole enclosure after material change.

Or if you have a good liquid proof mill enclosure and coolant drainage system, maybe you can just run a tap and wash the chips onto the drain collector for fast cleaning. My system isnt retrofitted with coolant drainage yet so thats not possible for me yet.

[WOTDesigns]

interesting idea on the separator. got a link?

I have two vacs, one for "dirty" things and then I picked up a wall mounted portable unit from lowes that has a rigid angled handle with a remote in it. the vac is behind the mill on the wall and I jam the wand into the handle on the vac so it sticks out about 2' from the wall. that one is AL only. I just reach for the wand, hit the remote and I'm cleaning without moving. I set it up when doing manual milling and it was a life saver.

I too haven't gotten around to making my flood enclosure. I have two pond pumps (first one was to low gph), bar drain with screen, tub, some plumbing, and a two head loc line set up. oh, and a quart of Rust-Bullet. from what I understand it is used on naval ships and dries hard as a rock, waterproof and slick. one guy coated some wood and left it in acid for a month and it was fine, lol.

BUT... I bought a Kool Mist portable for a temporary solution and it works so welli haven't been able to justify spending a weekend or two building an enclosure.

I think I need a new o ring in my loc line though. now the coolant retracts all the way back to the bottle every night and takes forever to draw back up.

[noobCNC]

You make a contraption that is designed to generate cyclones, essentially a fluid dynamic centrifuge, and then throw some kind of holding forces into the system (often just gravity if you create a vertical axis cyclone) and you get mass separation with the mass collecting at the bottom. Here are some CFD simulations of a cyclonic separator:

[ame=http://www.youtube.com/watch?v=BicR3JGlE5M&feature=related]Gas cyclone (effect of solid flow rate).wmv - YouTube[/ame]

Some people adapted them to workshops too:

[ame=http://www.youtube.com/watch?v=GuB6H67Q_7A&feature=related]Shop Vac Cyclone Wood Working - YouTube[/ame]

However I'd imagine you still cant achieve 'fool proof' non-contamination if you are sharing the same suction hose though between different materials, since especially if you use any kind of coolant or cutting oil, dust particles can stick to the vacuum tube and that may end up becoming dislodged and contaminating your other separated batches of chips. However they should hopefully be minor. The best way of course will cost the most also and that is maybe get a vacuum for each material, or one mill for each material, or at least one vacuum tube and one bin collector for each material if you are using this technique.

Making a mist coolant system is in the works for my mill too. I did build an enclosure a while ago but that is more for keeping the dust inside the work volume. I still do the old fashioned cutting oil drip bottle and vacuum technique.